Maintaining proper conditions of rail components of a railroad track is of paramount importance in the railroad transportation industry. Rail components include joint bars, fasteners, switches, frogs, ties, ballast, etc., as well as the rail segments themselves which form the railroad track. The condition of the railroad track greatly impacts safety and reliability of rail transportation. Failure or degradation of various rail components of a railroad track can cause derailment of a train traveling on the track. Such derailment can cause significant property damage and injury to passengers, crew and bystanders.
Visual inspection is one way to monitor the condition of railroad track and to ensure that the track is in good condition. However, the quality of visual inspection is generally poor, especially when the visual inspection is performed from a hi-railer, which is a vehicle that has been modified to drive on railroad tracks. Such hi-railers are often used by an inspector to travel on the railroad track while simultaneously inspecting the railroad track.
The limitation of this prior art method of inspecting railroad components is that it is very difficult for the inspector to see small defects or damage in the railroad components while driving the hi-railer. This limitation is exacerbated by the fact that defects or damage to the rail portions of the turnouts, i.e. switch points, stock rails, frogs and closure rails, are especially difficult to see. Inspection that is performed on foot can provide better results, since the inspector can more closely and carefully inspect each of the rail components. However, inspection performed on foot is a slow and tedious process, requiring many hours to inspect several miles of railroad track.
U.S. Pat. No. 6,356,299 to Trosino et al. discloses an automated track inspection vehicle for inspecting a railroad track for various anomalies. The automated track inspection vehicle disclosed includes a self-propelled car equipped with cameras for creating images of the track. This reference discloses that a driver and an inspector visually inspect the track and right-of-way through a window in the vehicle, thereby identifying anomalies such as presence of weeds, blocked drain, improper ballast, missing clip, or defective tie. The reference further discloses that the images from the cameras are viewed by the inspector on a video terminal to detect anomalies on the railroad track. When anomalies are detected by the driver or the inspector, a signal is provided to store the video data for review by an analyst. The reference notes that the analyst reviews the stored video data to confirm the presence of an anomaly, and generates a track inspection report identifying the type and location of the anomaly, as well as the required remedial action.
The significant limitation of the inspection vehicle disclosed in Trosino et al. and the method taught therein requires the inspector to continually perform visual inspection of the railroad track while traveling on the railroad track, such inspection being not much better in quality than the conventional inspection method from a hi-railer noted above. The method taught also requires three trained individuals at the same time. In addition, the disclosed inspection vehicle requires the inspector to press an appropriate button, indicating the type of anomaly identified, in order for the vehicle to capture and store the images of the railroad track for review by the analyst.
If the inspector does not see the anomaly and/or push the appropriate button, no image that can be reviewed by the analyst is captured. Therefore, whereas the railcar vehicle of Trosino et al. is appropriate for inspecting a railroad track for large anomalies which are easily visible to the inspector, such as the presence of weeds, blocked drain, etc., the described inspection vehicle does not allow facilitated inspection of smaller rail components or smaller defects associated therewith. The reference further discloses that the inspection vehicle allows inspection of a railroad track at speeds of 30-50 miles per hour.
Other vehicle-based rail profile measurement systems are also known in the industry and are used to make large numbers of measurements of the rail head for evaluating the condition of the rail head of the running rails. When used for inspection or planning purposes, these rail head profile measurement systems are usually mounted on inspection vehicles, such as railroad track geometry inspection cars that can operate at high speed (80 plus mph or 125 kph) and record images every 5 to 20 feet (1.5 to 6 meters), depending on actual measurement speed.
This type of system allows rail wear information to be obtained on the running rails, together with the detailed rail profiles. Thus these rail head measurement systems provide information for planning of both rail-grinding and rail replacement (re-laying) activities.
There are currently several such optical- or laser-based systems that are commercially available and in active use. They generally follow the same principle, using a light source or laser to illuminate the rail head. The illuminated rail profile is then recorded by a CCD (charge-coupled device) camera or related recording device, and the image stored in a digitized format. The ORIAN system, distributed by KLD Labs, Inc., represents one such commercially available system that is used on both inspection vehicles and rail grinders. A second commercially available rail measuring system is the Laserail system, distributed by ImageMap, Inc., which is likewise used on both high-speed inspection vehicles and low-speed rail grinders. Other systems, such as the VISTA system, a product of Loram, Inc., are of more limited application, primarily on rail grinders.
While these systems all generate digitized rail head profiles for the running rails, the exact extent of the measured rail head is limited by the number of cameras used and the “shadow” of the rail heads themselves. Thus, in all cases, they do not get a complete rail head image but a full top-of-rail profile, parts of the side of the rail head, and portions of the rail web and base. The bottom of the rail head is almost always obscured and lost, as is the bottom of any lip on the rail head. This does, however, allow for sufficient information to be obtained to accurately monitor the profile of the rail head as well as obtain rail-wear information.
In addition, while these systems generate digitized rail head profiles for the running rails, they do not analyze or generate digitized profiles for switches, frogs or other such components of turnouts. The usefulness of such prior systems has been limited to running rails.
Therefore, in view of the above, there exists a need for a better system for inspecting rail components of a railroad track, and a method thereof. In particular, there still exists a need for a system and method that allow accurate and efficient inspection of the rail portion of turnouts, which include the switch point, stock rail, frog and closure rail.